Discovery of a supercluster in the ZOA in Vela

Abstract

We report the discovery of a potentially major supercluster that extends across the Galactic Plane in the constellation of Vela, at a mean recessional velocity of ~18,000 km/s. Recent multi-object spectroscopic observations of this Vela Supercluster (VSCL), using AAOmega+2dF and the Southern African Large Telescope, confirm an extended galaxy overdensity in the Zone of Avoidance (ZOA) located where residual bulk flows predict a considerable mass excess. We present a preliminary analysis of ~4,500 new spectroscopic galaxy redshifts obtained in the ZOA centred on the Vela region (l=272.5+-20 deg, b=0+-10 deg). The presently sparsely-sampled dataset traces an overdensity that covers 25 deg in Galactic longitude on either side of the Plane, suggesting an extent of 25 deg x 20 deg, corresponding to ~115 x 90 $h_{70}$ Mpc at the supercluster redshift. In redshift space, the overdensity appears to consist of two merging wall-like structures, interspersed with clusters and groups. Both the velocity histogram and the morphology of the multi-branching wall structure are consistent with a supercluster classification. $K_s^o$ galaxy counts show an enhancement of ~1.2 over the survey area for galaxies brighter than $M_K^{\ast }$ at the VSCL distance, and a galaxy overdensity of $\delta =0.50-0.77$ within a photometric redshift shell around the VSCL, when compared to various Two-Micron All-Sky Survey samples. Taking account of selection effects, the VSCL is estimated to contribute $v_\rm{LG} \gtrsim 50$ km/s to the motion of the Local Group.

arXiv commentMatches the final version published in MNRAS Letters. Updated author list, spelling, references

References in corpus (35)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• The Cosmic Microwave Background Spectrum from the Full COBE/FIRAS Data Set
• The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
• 2MASS Extended Source Catalog: Overview and Algorithms
• The 2MASS Redshift Survey - Description and Data Release
• Cosmicflows-3
• The K-Band Galaxy Luminosity Function
• Consistently Large Cosmic Flows on Scales of 100 Mpc/h: a Challenge for the Standard LCDM Cosmology
• Detecting filamentary pattern in the cosmic web: a catalogue of filaments for the SDSS
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• The 2M++ galaxy redshift catalogue
• 2MASS Photometric Redshift catalog: a comprehensive three-dimensional census of the whole sky
• Cosmic Flows on 100 Mpc/h Scales: Standardized Minimum Variance Bulk Flow, Shear and Octupole Moments
• The 6dF Galaxy Survey: Peculiar Velocity Field and Cosmography
• Cosmic flow from 2MASS redshift survey: The origin of CMB dipole and implications for LCDM cosmology
• Streaming motions of galaxy clusters within 12000 km/s - V. The peculiar velocity field
• The Dipole Anisotropy of the 2 Micron All-Sky Redshift Survey
• The cosmological bulk flow: consistency with $\Lambda$CDM and $z\approx 0$ constraints on ${\sigma }_8$ and $\gamma$
• The 6dF Galaxy Survey: Bulk Flows on $50-70h^{-1}$ Mpc scales
• The extended ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II) IV. X-ray Luminosity Function and First Constraints on Cosmological Parameters
• On The Origin of the Local Group's Peculiar Velocity
• The Universe behind the Milky Way
• Constructing a WISE High Resolution Galaxy Atlas
• Cosmic Bulk Flow and the Local Motion from Cosmicflows-2
• SDSS superclusters: morphology and galaxy content
• The Parkes HI Zone of Avoidance Survey
• The extended ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey (REFLEX II) III. Construction of the first flux-limited supercluster sample
• SDSS DR7 superclusters. Morphology
• The velocity field of 2MRS Ks=11.75 galaxies: constraints on beta and bulk flow from the luminosity function
• Is the 2MASS clustering dipole convergent?
• Structure and dynamics of the Shapley Supercluster
• 2MTF V. Cosmography, Beta, and the residual bulk flow
• A Catalog of Galaxies behind the Southern Milky Way. - I. The Hydra/Antlia Extension (l: 266 - 296 deg)
• Dynamical Constraints on the Local Group from the CMB and 2MRS Dipoles

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• The VVV Near-IR Galaxy Catalogue beyond the Galactic disk
• A kinematic confirmation of the hidden Vela supercluster
• The whole picture of the large-scale structure of the CL1604 supercluster at z$\sim$0.9
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